[9] RFR of 8073078: java/nio/file/FileStore/Basic.java sensitive to NFS configuration

[Brian Burkhalter]

Please review at your convenience.

Issue:	https://bugs.openjdk.java.net/browse/JDK-8073078
Patch:	http://cr.openjdk.java.net/~bpb/8073078/webrev.00/

This intermittent failure, which https://bugs.openjdk.java.net/browse/JDK-8081354 likely duplicates, appears to occur only on Unix platforms, and based on code inspection and an isolated test on OS X, seems to be due to the Java permissions of the FileStore being checked in the object returned by FileSystem.getFileStores() without the accessibility of the FileStore actually being checked. Consequently when spurious or inaccessible mount points appear a NoSuchFileException results. This change should omit the transient mount point from the iteration per the documentation of FileSystem.getFileStores():

"When an I/O error occurs, perhaps because a file store is not accessible, then it is not returned by the iterator.”

The usual core NIO regression tests passed on two test queues.

Thanks,

Brian